Improvement in screw-cutting dies



E. A. STIMSQN.

SCREW cw'rnm DIES.

Patented April,1876.

N.PETERS. FNOTO-L1THDGRAFHER. WASHINGTON. D C.

Urvrrn EDWARD A. STIMSON, OF DAYTON. OlllO, ASSIGNOR OF ONE-HALF TITSRIGHT TO RBENEZER F. QTODDART), OF SAME PLACE.

IMPROVEMENT EN SQREW- CUTTING DIES.

Specification forming part of Letters Patent No. El 35,579, dated April4, 1876; application filed February 17 1876.

To all whom it may concern:

Be it known that I, EDWARD A. STIMSON, of Dayton, in the county ofMontgomery and State of Ohio, have invented certain new and usefulImprovements in Screw-Cutting Dies; and I do hereby declare thefollowing to be a full, clear, and exact -'(lescription of the same.

This invention relates to that class of dies which are used as tools ina lathe, and are pro vided with adjustable radially-moving chasers orcuttin g-jaws for formiu g threads upon stems, pipes, 850., in steam,gas, and other fittings;

' and my improvements consist in the formation of the body or stockrecessed radially for containing the cutters, and in the applicationthereto of an encircling ring having slotted cambeari u gs arranged withit for actuating the cutters and giving them a strong and solid rearbearing; also, in the combination and arrangement of a handle, aspring-catch, and an index latch-plate, all as will be herewithdescribed, and the invention distinctly pointed out in the claims.

To enable others skilled in the art to which my invention appertains tomake and use the same, I would thus proceed to describe its constructionand mode of operation, referring throughout to the accompanyingdrawings, in which Figure 1 is a face view of my improved die. Fig. 2 isthe reverse view of Fig. 1. Figs. 3, 4, and 5 represent minor devices,which will be referred to in the body of the specification.

Corresponding letters of reference indicate like parts in all thefigures.

A represents the die-stocks, which is a disk having on its face aradially-recessed boss, B, in the recesses of which are confined thechasers or cutting-jaws 0. Each of these cutters is formed with a gib,a, extending along one side near the bottom, which is keyed in a corresponding slot in the side of each recess, as seen in the sectionalview in Fig. 3. Dis a ring that fits snugly over the die-stock. and isprovided with equidistant cam projections E on its outer and innersurfaces, as is seen in Fig. 1. The faces of these projections areparallel, and each is slotted longitudinally and through the ring. Aface view of one of these cam projections is represented by the dottedlines D in Fig. 3. The chasers 0 have their rear ends resting againstthe inner faces of the cam projections E, and the ring and stock areconnected together by pins or studs 0, that are passed through the slotsin said projections, and are screwed or in any convenient manner securedto the rear ends of the chascrs 0. These pins lit snugly in the slots,and are provided with heads which rest against the outer faces of thecams, as seen in Fig. 4. To connect the ring and stock more firmly, soas to resist pressure during the ac tion of the die, the ends of theboss on each side of the recesses extend over the interior camprojections E, Figs. 1 and at. The rear face of the die is provided witha chuck, F, or any suitable device for connecting it to thelathe-mandrel. G is a handle, secured to the periphery of the ring 1),and provided with a bearing, 0, in which, and in the beariugfupou thering, the latch g, kept to its seatby the spiral spring h, works. Athumb-lever, i, pivoted in the handle G, and having the latchrod 9pivoted to it, serves to actuate the latter, whose projecting endengages with aseat in the arc-shaped slotted index-plate H, which issecured upon the rear face of the stock, Fig. 2, by screws j that passthrough the slots in the plate H and clamp it to the stock.

A graduated scale upon the face of the stock,in connection with acorresponding scale upon the plate II, enables-the die to be adjusted tothe work with the greatest precision.

It will be noticed that there are no projections extending from thecutting-surface of the die, and that the surfaces of the ring, the boss,and the cutters are inthe same plane.

Supposing the die to be attached to a lathe, its operation is asfollows: After being pre sented to the work in the usual manner, and thethread being on t, the operator releases the latch from its seat, turnsthe ring by means of the handle, when the exterior cum-faces, actingupon the heads of the pins 0, withdraw the chasers and allow the die tobe removed. The interiorcaui-i'aces, when the ring is turned move thechascrs inward, and form a solid unyielding rear bearing that is muchsuperior to the pins which usually extend from the chasers, and which,variously arranged in connection with slots, form the only supports forholding the chasers during the action of the die.

Having thus fully described both the construction and mode of operationof my invention, what I claim as new, and desire to secure by'LettersPatent, is as follows:

1. The die-stock A, having formed with it a radially-recessed boss, B,in combination with the cha-sers (J, formed with gibs upon their sides,that work in key-seats in the recesses of said boss, and provided withpins 0, confined in slots of the encircling ring" D, Whose interior cznnprojections form a solid rear hearing for the chasers, in the manner andfor the purpose specified.

EDWARD A. STIMSON. Witnesses:

OHAs. M. PEcK, WM. RITCHIE.

